Semiconductor device, manufacturing method, and electronic apparatus

ABSTRACT

A method of manufacturing a semiconductor device includes: forming, on a cover glass, a film having a predetermined specific gravity and configured to shield an alpha ray that arises from the cover glass; and bonding the cover glass on which the film is formed and an image pickup device, by filling a transparent resin between the cover glass and the image pickup device.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application claims priority to Japanese Priority PatentApplication JP 2013-046835 filed in the Japan Patent Office on Mar. 8,2013, the entire content of which is hereby incorporated by reference.

BACKGROUND

The present application relates to a semiconductor device, amanufacturing method, and an electronic apparatus. More specifically,the technology relates to a semiconductor device, a manufacturingmethod, and an electronic apparatus that reduce an influence of an alpharay that arises in a cover glass.

For an image pickup device, a configuration is known that encapsulatesan image pickup device chip, which is diced into an individual piece,from a wafer in the inside using a ceramic or plastic package having aconcave portion and a cover member. In such an image pickup device, ithas been found that, when glass is used as a cover member, an alpha raywhich is emitted from heavy metals contained in the glass has an adverseeffect on the characteristics of the image pickup device chip. InJapanese Unexamined Patent Application Publication Nos. 2012-49400,2006-137368, and 2007-173586, a structure for alleviating the influenceof the alpha ray on the image pickup device has been proposed.

Further, a WL-CSP (Wafer Level Chip-Size Package) is known that fixes asemiconductor substrate having an image pickup device in a wafer formand a light-transmissive substrate to dice such substrates intoindividual chip pieces. For an image pickup device fabricated based onWL-CSP, a batch processing at a wafer level is possible, and thusreduction of manufacturing costs, as well as the manufacturability offurther small-sized and thin image pickup device are expected.

SUMMARY

Japanese Unexamined Patent Application Publication No. 2012-49400 hasproposed to prevent an image pickup white spot defect that is caused dueto the influence of an alpha ray by forming an alpha-ray-shielding filmon a cover glass. In Japanese Unexamined Patent Application PublicationNo. 2012-49400, the alpha-ray-shielding film is bonded against the glasswith a transparent adhesive, and thus in a case of a structure ofbonding an Si wafer and a cover glass wafer like the WL-CSP inparticular, it is necessary to bond the alpha-ray-shielding filmsindividually on cover glasses corresponding to respective pixelsections. Such a technology involves a process for bonding thealpha-ray-shielding films individually on the cover glassescorresponding to the respective pixel sections, posing a possibility ofan increase in length of time of an overall process.

Further, in the image pickup device disclosed in Japanese UnexaminedPatent Application Publication No. 2012-49400, a hollow structure isformed on the image pickup device, and thus in a case of producing theWL-CSP exceeding 10 mm in size, especially in a case of producing athrough electrode at the image pickup device side, an Si portion of theimage pickup device is reduced in thickness. As a result, there is apossibility that the reliability will deteriorate because the imagepickup device may be easily damaged.

Japanese Unexamined Patent Application Publication No. 2006-137368 hasproposed to reduce the influence of an alpha ray by setting a thicknessof a transparent adhesive to 20 μm or more in a Cavityless WL-CSP thatadopts a structure in which an image pickup device and a cover glass arebonded with one another with the transparent adhesive.

In the Japanese Unexamined Patent Application Publication No.2006-137368, an increase in the thickness of the transparent adhesivemay raise the amount of warpage in a thermal history during amanufacturing process, which may pose an issue of concern for a defectduring a backside wiring process, wafer cracking, and detachment betweenthe transparent resin and the cover glass or the image pickup device.Further, it is difficult to reduce the transparent adhesive inthickness, which makes it difficult to achieve the reduction inthickness of CSP.

Japanese Unexamined Patent Application Publication No. 2007-173586 hasproposed a structure for shielding of an alpha ray in such a manner thatan oxide film is formed at the image pickup device side, and this isbonded with a cover glass using a transparent resin. In the JapaneseUnexamined Patent Application Publication No. 2007-173586, because apatterning is not performed after forming the oxide film, the amount ofwarpage of an image pickup device section increases and a thickness ofthe oxide film that is allowed to be formed is limited, which makes itdifficult to reduce the transparent resin in thickness. Further, becausethe oxide film is formed at the CIS side, the oxide film to be formed islimited to the oxide film that is allowed to be formed at lowtemperature.

It is desirable to provide a technology that allows an influence of analpha ray to be reduced.

According to an embodiment of the present application, there is provideda semiconductor device including: an image pickup device; a cover glass,the image pickup device and the cover glass being bonded to one another;a film provided between the image pickup device and the cover glass, thefilm having a predetermined specific gravity and configured to shield analpha ray that arises from the cover glass; and a transparent resinfilled between the image pickup device and the cover glass.

Advantageously, the following Expression may be satisfied:AX+BY≧C(in μm)

where a thickness of the film is A in μm, a thickness of the transparentresin is B in μm, the specific gravity of the film is X, a specificgravity of the transparent resin is Y, and a distance between the coverglass and an imaging surface of the image pickup device is C, thedistance being calculated as a distance necessary to reduce an influenceof the alpha ray on the basis of a range of the alpha ray emitted fromuranium contained in the cover glass.

Advantageously, the film may be formed on the cover glass.

Advantageously, the film may be formed only at a region corresponding toportions where pixels of the image pickup device are provided.

In the semiconductor device according to any of the above-describedembodiments of the present application, the image pickup device and thecover glass are so provided that the film having a predeterminedspecific gravity and the transparent resin are filled. The film has afunction of shielding the alpha ray arising from the cover glass.

According to an embodiment of the present application, there is provideda method of manufacturing a semiconductor device, the method including:forming, on a cover glass, a film having a predetermined specificgravity and configured to shield an alpha ray that arises from the coverglass; and bonding the cover glass on which the film is formed and animage pickup device, by filling a transparent resin between the coverglass and the image pickup device.

Advantageously, the film may be formed to have a thickness thatsatisfies the following Expression:AX+BY≧C(in μm)

where the thickness of the film is A in μm, a thickness of thetransparent resin is B in μm, the specific gravity of the film is X, aspecific gravity of the transparent resin is Y, and a distance betweenthe cover glass and an imaging surface of the image pickup device is C,the distance being calculated as a distance necessary to reduce aninfluence of the alpha ray on the basis of a range of the alpha rayemitted from uranium contained in the cover glass.

Advantageously, the method may further include, after the forming thefilm on the cover glass, removing the film at a portion corresponding toa scribing line.

In the manufacturing method according to any of the above-describedembodiments of the present application, the semiconductor device ismanufactured by forming, on the cover glass, the film having apredetermined specific gravity and having a function of shielding thealpha ray arising from the cover glass; and bonding the cover glass onwhich the film is formed and the image pickup device by filling thetransparent resin.

According to an embodiment of the present application, there is providedan electronic apparatus provided with a semiconductor device and asignal processing section. The signal processing section is configuredto perform a signal processing for a pixel signal outputted from thesemiconductor device. The semiconductor device includes: an image pickupdevice; a cover glass, in which the image pickup device and the coverglass are bonded to one another; a film provided between the imagepickup device and the cover glass, in which the film has a predeterminedspecific gravity and configured to shield an alpha ray that arises fromthe cover glass; and a transparent resin filled between the image pickupdevice and the cover glass.

In the electronic apparatus according to the above-described embodimentof the present application, the semiconductor device and the signalprocessing section are included. The image pickup device and the coverglass are so provided that the film having a predetermined specificgravity and the transparent resin are filled. The film has a function ofshielding the alpha ray arising from the cover glass. The signalprocessing section is configured to perform a signal processing for apixel signal outputted from such a semiconductor device.

According to the above-described embodiments of the present application,it is possible to reduce an influence of an alpha ray.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the technology as claimed.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings are included to provide a furtherunderstanding of the present disclosure, and are incorporated in andconstitute a part of this specification. The drawings illustrateembodiments and, together with the specification, serve to explain theprinciples of the present application.

(A) and (B) of FIG. 1 are each a schematic diagram showing aconfiguration of a semiconductor device according to a first embodimentof the present application.

FIGS. 2A to 2H are each a schematic diagram for explaining amanufacturing process of the semiconductor device according to the firstembodiment of the present application.

FIG. 3 is a side view showing a configuration in the manufacturingprocess of the semiconductor device.

FIGS. 4A and 4B are each a schematic diagram showing a configuration ofa semiconductor device according to a second embodiment of the presentapplication.

FIGS. 5A to 5J are each a schematic diagram for explaining amanufacturing process of the semiconductor device according to thesecond embodiment of the present application.

FIG. 6 is a schematic block diagram showing a configuration of an imagepickup apparatus.

DETAILED DESCRIPTION

Hereinafter, the description is provided on some embodiments of thepresent application (hereinafter referred to as “embodiment(s)”. Thedescription is provided in the order given below.

-   1. Configuration of a semiconductor device according to a first    embodiment-   2. Manufacturing of the semiconductor device according to the first    embodiment-   3. Configuration of a semiconductor device according to a second    embodiment-   4. Manufacturing of the semiconductor device according to the second    embodiment-   5. Configuration of an image pickup apparatus

(Configuration of Semiconductor Device According to First Embodiment)

(A) and (B) of FIG. 1 are each a schematic diagram showing aconfiguration of a semiconductor device according to a first embodimentof the present application. (A) of FIG. 1 is a perspective plan view ofthe semiconductor device, and (B) of FIG. 1 is a schematiccross-sectional view along X-X′ line denoted in (A) of FIG. 1.

The semiconductor device has an image pickup device chip 1 having apixel region 4, and a light-transmissive cover member 2 that is fixed tothe image pickup device chip 1 through a fixing member 3. As describedlater, this semiconductor device is fabricated in such a manner that asemiconductor wafer and a light-transmissive substrate are fixed withone another by means of the fixing member 3, and thereafter are dicedinto individual chip pieces. The image pickup device chip 1 may be, forexample, a CMOS (Complementary Metal Oxide Semiconductor) image sensor,a CCD (Charge Coupled Device) image sensor, or the like. The pixelregion 4 has a plurality of conversion elements for converting incidentlight into charges as well as a plurality of transistors.

On a semiconductor substrate 11 of the image pickup device chip 1, thereare arranged microlenses 12 and a color filter 13. On the underside ofthe semiconductor substrate 11 (opposite side of light incidence side),there are arranged a conductive film 16, an insulating film 18, and aninsulating member 19. A material such as Al (aluminum) or Cu (copper)may be used for the conductive film 16, and a material such as an oxidefilm or a nitride film may be used for the insulating film 18 may use.Further, a material such as a solder resist may be used for theinsulating member 19.

The image pickup device chip 1 has a through electrode 15 that runsthrough a first principal surface on the light-transmissive cover memberside that is the light incidence side of the semiconductor substrate 11and a second principal surface on the opposite side of the firstprincipal surface. The through electrode 15 is configured by a part ofthe conductive film 16. The through electrode 15 is electricallyconnected with a surface electrode 14 within a wiring structure.Further, for electrical connection with a circuit substrate that is notshown in the drawing, the image pickup device chip 1 has a wire 17 thatis configured by a part of the conductive film 16.

Additionally, the image pickup device chip 1 has connection terminals 20for connection with an external circuit that are electrically connectedwith the wire 17 arranged on the opposite side of the light-transmissivecover member 2. A solder ball is used for each of the connectionterminals 20 in this example, although an anisotropic conductive membersuch as an ACP (Anisotropic Conductive Paste) or an ACF (AnisotropicConductive Film) may be used for the connection terminals 20. A siliconsubstrate is used for a CMOS image sensor as the image pickup devicechip 1.

The light-transmissive cover member 2, for which a configuration after alight-transmissive substrate is diced into individual chip pieces isillustrated in the drawing, has a cover glass 31 and an oxide film 32.When the amount of an alpha ray emitted from the light-transmissivecover member 2 is greater than a predetermined value, it is likely thatthis will cause a malfunction of the image pickup device chip 1 ordeterioration in the image quality, and thus it is necessary to reducethe emission amount of the alpha ray. Accordingly, as thelight-transmissive cover member 2, the cover glass 31 and the oxide film32 that is for reducing radiation of the alpha ray onto the image pickupdevice chip 1 are used in combination with one another. The oxide film32 functions as an alpha ray shielding film.

As described with reference to FIGS. 2A to 2H, the oxide film 32 isconfigured on the cover glass 31. In the first embodiment of the presentapplication, the description is provided on the assumption that theoxide film 32 with the area equivalent to that of the cover glass 31 isprovided on the cover glass 31. More specifically, in (B) of FIG. 1, theoxide film 32 is provided on the cover glass 31 seamlessly.

(Manufacturing of Semiconductor Device According to First Embodiment)

Next, a method of manufacturing the semiconductor device illustrated in(A) and (B) of FIG. 1 is described using FIGS. 2A to 2H. It is to benoted that FIGS. 2A to 2H are simplified as compared with (A) and (B) ofFIG. 1.

First, as shown in FIG. 2A, a plurality of pixel regions and the likeillustrated in (A) and (B) of FIG. 1 are formed on a substrate 51 thatis configured of a silicon single crystal, to prepare a semiconductorwafer 50 having the plurality of pixel regions 4. The pixel regions andthe like may be formed using a semiconductor device manufacturingprocess.

As shown in FIG. 2B, a light-transmissive substrate 60 is manufacturedby forming the oxide film 32 on the cover glass 31. The cover glass 31may preferably exhibit the linear expansion behavior with respect totemperature similar to that of Si (substrate 51 that is formed of asilicon single crystal) to the extent possible. Examples of such coverglass 31 may include quartz glass, borosilicate glass, and the like.

The oxide film 32 is formed by adopting a film-forming method, such asCVD (Chemical Vapor Deposition) using P—SiO, SOG, and TEOS that containno radioactive elements including uranium, or SOG (Spin On Glass). Thefilm-forming method of the oxide film 32 may preferably be a method thatallows formation of the oxide film 32 at a predetermined thickness.Further, any oxide film that is allowed to be formed in a method such asthe CVD and spin coating may be applicable as the oxide film 32.

Additionally, a material having a specific gravity of a value equal toor greater than a predetermined value, for example, about two or more isused for the oxide film 32. Use of the oxide film 32 having the highspecific gravity material makes it possible to shield the alpha rayefficiently. Such an efficient shielding capability of the alpha rayallows shielding of the alpha ray even with the thin oxide film 32,which makes it possible to reduce the oxide film 32 in thickness.Further, reduction in thickness of the oxide film 32 enables thesemiconductor device itself (CSP) to be reduced in thickness.

A thickness of the oxide film 32 may be determined based on arelationship with a thickness of the fixing member 3 (for which atransparent resin or the like may be used as described hereinafter).Even if the oxide film 32 is not provided, it is possible to reduce theinfluence of the alpha ray on the image pickup device by increasing athickness of the fixing member 3 to increase a distance between thecover glass 31 and the image pickup device (or the microlenses 12).

Accordingly, it is possible to reduce the influence of the alpha rayemitted from the cover glass 31 on the image pickup device by adjustingthe thickness of the oxide film 32 and the thickness of the fixingmember 3. Here, when a thickness of the oxide film 32 is A (in μm), athickness of the fixing member 3 (transparent resin that bonds the imagepickup device and the cover glass 31) is B (in μm), a specific gravityof the oxide film 32 is X, and a specific gravity of the fixing member 3is Y, the following Expression is established for a distance C betweenthe cover glass 31 and an imaging surface of the image pickup device.AX+BY≧C(in μm)

When the sum of a value obtained by multiplying the thickness of theoxide film 32 by the specific gravity of the oxide film 32 and a valueobtained by multiplying the thickness of the fixing member 3 by thespecific gravity of the fixing member 3 is greater than thepredetermined value C, it is possible to reduce the influence of thealpha ray emitted from the cover glass 31 because such an influence doesnot reach the imaging surface of the image pickup device.

The distance C is defined as a value calculated as a distance necessaryfor preventing an image pickup white spot defect caused by the alpha rayemitted from the cover glass 31, on the basis of a range of the alpharay emitted from uranium contained in the cover glass 31, for example.Based on this relational expression, when the thickness and the specificgravity of the fixing member 3 are each set to have a fixed value, itwill be appreciated that the oxide film 32 is allowed to be reduced inthickness when the specific gravity of the oxide film 32 is large.Further, obviously, it will also be appreciated that provision of theoxide film 32 allows the fixing member 3 to be reduced in thickness moreas compared with a case of provision of only the fixing member 3.

In such a manner, by increasing the thickness of the oxide film havingthe specific gravity typically higher than that of a resin, it ispossible to reduce a thickness of a transparent resin (thickness of thefixing member 3), leading to reduction in thickness of the CSP.

It is to be noted that the thickness of the oxide film 32 may not becalculated only from the above relational expression, but may becalculated based on any other expression.

Referring back to the description with respect to FIGS. 2A to 2H, asillustrated in FIG. 2C and FIG. 2D, the semiconductor wafer 50 and thelight-transmissive substrate 60, which is manufactured to have a sizeabout the same size as the semiconductor wafer 50, are overlapped withone another to be fixed. The semiconductor wafer 50 and thelight-transmissive substrate 60 are fixed with the fixing member 3. Aliquid adhesive may be used for the fixing member 3. Further, forexample, a transparent resin may be used for the fixing member 3, andthe transparent resin may be hardened to fix (bond) the semiconductorwafer 50 and the light-transmissive substrate 60.

For a transparent adhesive as the fixing member 3, silicon resin,acrylic resin, epoxy resin, dendrimer, or copolymer thereof may beselected. Such a selection ensures that any disadvantage in terms of theheat resistance/chemical resistance/light resistance is not caused in aprocess subsequent to bonding of the semiconductor wafer 50 and thelight-transmissive substrate 60 (for example, a heat-based orUV-irradiation-based hardening treatment) or also in a reliability test,and that the image pickup characteristics are not influenced.

Further, use of a transparent resin that enables formation of a resinfilm in a coating or lamination method on the semiconductor wafer 50side or on the cover glass 31 side where the oxide film 32 is formed,and capable of performing bonding of the image pickup device or thecover glass 31 on which the oxide film 32 is formed in a semi-hardenedstate makes it possible to prevent protrusion of resin to a wafer edgeor generation of a resin void during the bonding process.

In this manner, the light-transmissive substrate 60 on which the oxidefilm 32 is formed is overlapped with the semiconductor wafer 50 on thecover glass 31. A surface to be overlapped with the semiconductor wafer50 is a surface on which the oxide film 32 is provided.

As shown in FIG. 2E, the semiconductor wafer 50 is reduced in thickness.As a method for reducing the thickness, one or more of backgrinding, CMP(Chemical Mechanical Polishing), and etching methods may be selected. Onthis occasion, the semiconductor wafer 50 is reduced in thickness as faras a state where formation of the through electrode is allowed in asubsequent-stage process. As illustrated in FIG. 2E, in the state wherethe semiconductor wafer 50 is reduced in thickness, a space between thecover glass 31 and the image pickup device is not of a hollow structurebecause the oxide film 32 and a transparent resin (fixing member 3) arefilled between the cover glass 31 and the image pickup device.

Therefore, in a case of a hollow structure, the strength deteriorates inthe hollow structure portion, resulting in degradation in thereliability. However, it is possible to avoid such a disadvantage, andto achieve a thin WL-CSP that assures the high reliability.

As shown in FIG. 2F, the through electrode 15 is formed on thesemiconductor wafer 50. For the through electrode 15, a through hole isformed by etching to open a wiring portion of multi-layer wiring (notshown in the drawing) that is formed on the surface of the semiconductorwafer. Subsequently, an insulating film such as a silicon oxide film isformed, and the insulating film inside the through hole is opened byetching. Thereafter, the through electrode is formed inside the throughhole by means of, for example, Cu plating, and the wiring is formed onthe surface (backside) at the opposite side of the light-transmissivesubstrate of the semiconductor wafer. Afterward, a solder resist as aninsulating member is formed at the backside of the semiconductor wafer,and an aperture is formed on the wiring to form solder balls as theconnection terminals 20.

As shown in FIG. 2G, the semiconductor wafer 50 and thelight-transmissive substrate 60 that are integrated with one another arediced into individual chip pieces. In FIG. 2G, a reference numeral 71denotes a dicing position. As a dicing method, blade dicing, laserdicing, and the like may be used. The laser dicing may be a preferablemethod because this is excellent in the machining performance for thesemiconductor wafer that is reduced in thickness, and this makes itpossible to reduce a dicing width as well as to prevent generation ofburr of a dicing surface.

As shown in FIG. 2H, the processes as described above complete thesemiconductor device.

FIG. 3 shows a side view of the semiconductor wafer 50 and thelight-transmissive substrate 60 that are integrated with one anotherbefore being diced into individual chip pieces, and is a schematicdiagram extracting two semiconductor devices from the semiconductorwafer 50 and the light-transmissive substrate 60 that are integratedwith one another as illustrated in FIG. 2G. As shown in FIG. 3, thecover glass 31 and the oxide film 32 are arranged in this order from thetop, and the light-transmissive substrate 60 is integrated with thesemiconductor wafer 50 through the fixing member 3. The oxide film 32 isprovided as a layer seamlessly between the cover glass 31 and the fixingmember 3. Accordingly, when the integrated semiconductor wafer 50 andthe light-transmissive substrate 60 having such an oxide film 32 arediced into individual chip pieces, the form thereof is as shown in (B)of FIG. 1.

The oxide film 32 makes it possible to prevent the alpha ray arising inthe cover glass 31 from reaching the imaging surface of the image pickupdevice. For example, it is possible to reduce the likelihood that adrawback such as a white spot defect will be caused by the alpha ray.Further, use of low-alpha-ray glass may be contemplated to reduce theinfluence of the alpha ray, although the oxide film 32 is allowed to beprovided more inexpensively than the low-alpha-ray glass, resulting inthe cost reduction being achieved. Additionally, the low-alpha-ray glassmakes it difficult to adjust the linear expansion coefficient to that ofsilicon (Si) at the image pickup device side. In contrast, the method ofproviding the oxide film 32 on the cover glass 31 makes it easy toadjust the linear expansion coefficient to that of the silicon at theimage pickup device side.

Further, if the cover glass 31 and the semiconductor wafer 50 areintegrated with one another without providing the oxide film 32, it isdifficult to reduce the influence of the alpha ray unless the fixingmember 3 is increased in thickness. More specifically, in a case of astructure without providing the oxide film 32, it is necessary to reducethe influence of the alpha ray by increasing the thickness of the fixingmember 3, which makes it difficult to achieve the thin semiconductordevice. On the contrary, the structure of providing the oxide film 32makes it possible to achieve the thin semiconductor device.

(Configuration of Semiconductor Device According to Second Embodiment)

In the first embodiment of the present application, the description isprovided by taking as an example a case where the oxide film 32 isprovided on the cover glass 31 seamlessly, in other words, a case wherethe oxide film 32 is provided over the whole surface of the cover glass31. In the second embodiment of the present application, the descriptionis provided by taking as an example a case where the oxide film 32 isprovided in a state in which the oxide film 32 has a seam partially onthe cover glass 31, in other words, a state in which the oxide film 32is partially removed on the cover glass 31.

FIGS. 4A and 4B are each a schematic diagram showing a configuration ofa semiconductor device according to the second embodiment of the presentapplication. FIG. 4A corresponds to the semiconductor device illustratedin (B) of FIG. 1, and is a schematic diagram showing a configuration ofa single semiconductor device. The semiconductor device illustrated inFIG. 4A is different from the semiconductor device illustrated in (B) ofFIG. 1 in that the oxide film 32 is not provided in the vicinity of alocation of the through electrode 15 in the semiconductor deviceillustrated in FIG. 4A.

FIG. 4B corresponds to the semiconductor device illustrated in FIG. 3.FIG. 4B is a schematic diagram showing a configuration of twoconsecutive semiconductor devices before they are diced into individualchip pieces. As shown in FIG. 4B, the oxide film 32 is not provided at aportion of a scribing line (mark-off line). In other words, the oxidefilm 32 is not provided at a portion other than a pixel region of thesemiconductor device.

Further, in other words, with reference to (A) of FIG. 1, a structure isadopted where the oxide film 32 is provided at a portion correspondingto the pixel region 4, but the oxide film 32 is not provided at aportion corresponding to any portion other than the pixel region 4 (theoxide film 32 is removed during a manufacturing process as describedlater).

As described above, by providing a region where the oxide film 32 is notprovided partially instead of providing the oxide film 32 continuously,it is possible to reduce the warpage of the cover glass 31.

(Manufacturing of Semiconductor Device According to Second Embodiment)

Next, a method of manufacturing the semiconductor devices illustrated inFIGS. 4A and 4B is described using FIGS. 5A to 5J. It is to be notedthat FIGS. 5A to 5J are simplified as compared with FIGS. 4A and 4B.

The manufacturing method illustrated in FIGS. 5A to 5J is the same inbasic flow as the manufacturing method described with reference to FIGS.2A to 2H with the exception of additional steps illustrated in FIG. 5Cand FIG. 5D. Therefore, the description that overlaps with thedescription with reference to FIGS. 2A to 2H is omitted as appropriate.

First, as shown in FIG. 5A, the semiconductor wafer 50 having theplurality of pixel regions 4 is prepared on the substrate 51 that isformed of a silicon single crystal. As shown in FIG. 5B, thelight-transmissive substrate 60 is manufactured by forming the oxidefilm 32 on the cover glass 31. In this process, the oxide film 32 isformed over a whole surface at one side of the light-transmissivesubstrate 60.

As shown in FIG. 5C, a resist 81 is coated on the cover glass 31 onwhich the oxide film 32 is formed, and the patterning is performed. Bycarrying out the patterning by the use of, for example, a photoresist,the light-transmissive substrate 60 in which the oxide film 32 on thescribing line (line having a predetermined width that is centered on thescribing line) is removed is manufactured as shown in FIG. 5D.

FIG. 5E to FIG. 5J are the same as FIG. 2C to FIG. 2H, and thus thedescription thereof is omitted.

In such a manner, by adding the process for removing the oxide film 32,it is possible to provide the oxide film 32 at a portion involving useof the oxide film 32 and removing the oxide film 32 at a portion notinvolving use of the oxide film 32. A portion involving use of the oxidefilm 32 may be, for example, a region within the pixel region 4, and aportion of the cover glass 31 corresponding to a portion where themicrolenses 12 are located.

By providing the portion where the oxide film 32 is removed, it ispossible to reduce the generation of the warpage. For example, it ispossible to reduce even the warpage arising when the oxide film 32 witha relatively larger thickness is formed on the cover glass 31.

By forming the oxide film 32 to have a larger thickness, it is possibleto reduce the influence of the alpha ray even when the oxide film 32having a small specific gravity is used. Further, depending on amaterial used for the oxide film 32, a predetermined thickness may benecessary for full effectiveness. In such a case, even though there is apossibility of occurrence of the warpage, removal of a part of the oxidefilm 32 allows generation of the possible warpage to be reduced.

Because removal of a part of the oxide film 32 allows the warpage to bereduced, it is possible to use the oxide film 32 with an inexpensivematerial, the oxide film 32 having a small specific gravity, or theoxide film 32 suitable for manufacturing. As a result, this makes itpossible to broaden the range of choice for the oxide film 32.

By carrying out a patterning after forming the oxide film 32 on thecover glass 31, it is possible to reduce the amount of warpage of thecover glass 31 that is caused due to formation of the oxide film 32.Further, this also makes it possible to prevent a defect during abonding process of the cover glass 31 and the image pickup device, adefect during a backside wiring process, wafer cracking, and the like.Moreover, it is possible to prevent detachment between the transparentresin (fixing member 3) and the cover glass 31 as well as detachmentbetween the fixing member 3 and the image pickup device.

Further, as described above, the bonding of the cover glass 31 to thesemiconductor wafer 50 is performed after the oxide film 32 is formed onthe cover glass 31 and a patterning is performed, which allows the oxidefilm 32 to be formed at high temperature, for example, at temperature ofabout 400 degrees centigrade or higher. For example, if the bonding ofthe semiconductor wafer 50 to the cover glass 31 is performed after theoxide film 32 is formed on the semiconductor wafer 50, the oxide film 32is limited to an oxide film that is allowed to be formed at lowtemperature, because the heat resistance of the semiconductor wafer 50is low and it is difficult to form the oxide film 32 at high temperaturein consideration of the influence of temperature on the semiconductorwafer 50. In other words, limitation of the process temperatureincreases, which makes it difficult to form the oxide film having alarge thickness in particular.

However, because the oxide film 32 is formed on the cover glass 31, itis possible to form the oxide film 32 at high temperature, and to usethe oxide film that is allowed to be formed at high temperature, as wellas to form a thick film. This allows the range of choice for usablematerials of the oxide film to be broadened, which makes it possible toincrease options for patterning methods and the like. In other words,according to an embodiment of the present application, it is possible toreduce limitation of film-forming temperature and film-forming methods,thereby allowing a degree of freedom for the process to be raised.

Further, as with the first embodiment of the present application, use ofthe oxide film 32 makes it possible to reduce the likelihood that adrawback such as a white spot defect will be caused by the alpha rayarising in the cover glass 31. Additionally, the oxide film 32 isallowed to be provided more inexpensively than the low-alpha-ray glass,resulting in the cost reduction being achieved. Moreover, the method ofproviding the oxide film 32 on the cover glass 31 makes it easier toadjust the linear expansion coefficient to that of the silicon at theimage pickup device side.

Further, the structure of providing the oxide film 32 on the cover glass31 achieves thin semiconductor device.

(Configuration of Image Pickup Apparatus)

The above-described semiconductor device is applicable to any electronicapparatus that uses semiconductor device for an image capture section(photoelectric conversion section), including an image pickup apparatussuch as a digital still camera and a video camera, a mobile terminalapparatus having a built-in image pickup function such as a mobilephone, and a copier using an image pickup apparatus at an image scannersection.

FIG. 6 is a schematic block diagram showing a configuration example ofan electronic apparatus according to an embodiment of the presentapplication, for example, an image pickup apparatus. As shown in FIG. 6,an image pickup apparatus 200 according to an embodiment of the presentapplication has an optical system including a lens group 201 and thelike, image pickup elements (image pickup device) 202, a DSP circuit203, a frame memory 204, a display unit 205, a recording unit 206, anoperation system 207, a power supply system 208, and the like. The DSPcircuit 203, the frame memory 204, the display unit 205, the recordingunit 206, the operation system 207, and the power supply system 208 areinterconnected with each other via a bus line 209.

The lens group 201 captures incident light (image light) from a subjectto form the image on an image pickup surface of the image pickup device202. The image pickup device 202 converts the amount of the incidentlight that is imaged on the image pickup surface by the lens group 201into an electrical signal on a pixel basis to output such a convertedsignal as a pixel signal.

The display unit 205 is configured of a panel-type display unit such asa liquid crystal display unit or an organic EL (Electro Luminescence)display unit, and displays moving images or still images that are imagedby the image pickup device 202. The recording unit 206 records themoving images or the still images that are imaged by the image pickupdevice 202 on a recording medium such as a video tape and a DVD (DigitalVersatile Disk).

The operation system 207 issues operation commands for various functionsthat the image pickup apparatus has under an operation by a user. Thepower supply system 208 provides various power supplies as operationpower supplies for the DSP circuit 203, the frame memory 204, thedisplay unit 205, the recording unit 206, and the operation system 207to these component parts as appropriate.

The image pickup apparatus that is configured as described above isapplicable as the image pickup apparatus including a video camera and adigital still camera, as well as a camera module for a mobile apparatussuch as a mobile phone. Further, in the image pickup apparatus, theabove-described semiconductor device is usable as the image pickupdevice 202.

It is to be noted that the present application is not limited to theabove-described embodiments, but various modifications are availableinsofar as they are within the scope of the substance of the presentapplication.

Furthermore, the technology encompasses any possible combination of someor all of the various embodiments described herein and incorporatedherein.

It is possible to achieve at least the following configurations from theabove-described example embodiments of the disclosure.

-   (1) A semiconductor device, including:    -   an image pickup device;    -   a cover glass, the image pickup device and the cover glass being        bonded to one another;    -   a film provided between the image pickup device and the cover        glass, the film having a predetermined specific gravity and        configured to shield an alpha ray that arises from the cover        glass; and    -   a transparent resin filled between the image pickup device and        the cover glass.-   (2) The semiconductor device according to (1), wherein the following    Expression is satisfied:    AX+BY≧C(in μm)    -   where a thickness of the film is A in μm, a thickness of the        transparent resin is B in μm, the specific gravity of the film        is X, a specific gravity of the transparent resin is Y, and a        distance between the cover glass and an imaging surface of the        image pickup device is C, the distance being calculated as a        distance necessary to reduce an influence of the alpha ray on        the basis of a range of the alpha ray emitted from uranium        contained in the cover glass.-   (3) The semiconductor device according to (1) or (2), wherein the    film is formed on the cover glass.-   (4) The semiconductor device according to any one of (1) to (3),    wherein the film is formed only at a region corresponding to    portions where pixels of the image pickup device are provided.-   (5) A method of manufacturing a semiconductor device, the method    including:    -   forming, on a cover glass, a film having a predetermined        specific gravity and configured to shield an alpha ray that        arises from the cover glass; and    -   bonding the cover glass on which the film is formed and an image        pickup device, by filling a transparent resin between the cover        glass and the image pickup device.-   (6) The method according to (5), wherein the film is formed to have    a thickness that satisfies the following Expression:    AX+BY≧C(in μm)    -   where the thickness of the film is A in μm, a thickness of the        transparent resin is B in μm, the specific gravity of the film        is X, a specific gravity of the transparent resin is Y, and a        distance between the cover glass and an imaging surface of the        image pickup device is C, the distance being calculated as a        distance necessary to reduce an influence of the alpha ray on        the basis of a range of the alpha ray emitted from uranium        contained in the cover glass.-   (7) The method according to (5) or (6), further including, after the    forming the film on the cover glass, removing the film at a portion    corresponding to a scribing line.-   (8) An electronic apparatus provided with a semiconductor device and    a signal processing section, the signal processing section being    configured to perform a signal processing for a pixel signal    outputted from the semiconductor device, the semiconductor device    including:    -   an image pickup device;    -   a cover glass, the image pickup device and the cover glass being        bonded to one another;    -   a film provided between the image pickup device and the cover        glass, the film having a predetermined specific gravity and        configured to shield an alpha ray that arises from the cover        glass; and    -   a transparent resin filled between the image pickup device and        the cover glass.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

The invention is claimed as follows:
 1. A semiconductor device,comprising: an image pickup device; a cover glass, wherein the imagepickup device and the cover glass are bonded to one another; a filmprovided between the image pickup device and the cover glass, whereinthe film has a specific gravity value of two or more and is configuredto shield an alpha ray that arises from the cover glass; and atransparent resin filled between the image pickup device and the coverglass, wherein the film is configured to cover an entire area of thetransparent resin within a pixel region.
 2. The semiconductor deviceaccording to claim 1, wherein the following Expression is satisfied:AX+BY>C(in μm) where a thickness of the film is A in μm, a thickness ofthe transparent resin is B in μm, the specific gravity of the film is X,a specific gravity of the transparent resin is Y, and a distance betweenthe cover glass and an imaging surface of the image pickup device is C,wherein the distance is calculated as a distance at which an influenceof the alpha ray based on a range of the alpha ray emitted from uraniumcontained in the cover glass is reduced.
 3. The semiconductor deviceaccording to claim 1, wherein the film is provided on the cover glass.4. The semiconductor device according to claim 1, wherein the film isprovided at a region that corresponds to portions where pixels of theimage pickup device are provided.
 5. A method of manufacturing asemiconductor device, the method comprising: forming, on a cover glass,a film that has a specific gravity value of two or more and isconfigured to shield an alpha ray that arises from the cover glass; andbonding the cover glass on which the film is formed and an image pickupdevice, by filling a transparent resin between the cover glass and theimage pickup device, wherein the film is configured to cover an entirearea of the transparent resin within a pixel region.
 6. The methodaccording to claim 5, wherein the film is formed to have a thicknessthat satisfies the following Expression:AX+BY>C(in μm) where the thickness of the film is A in μm, a thicknessof the transparent resin is B in μm, the specific gravity of the film isX, a specific gravity of the transparent resin is Y, and a distancebetween the cover glass and an imaging surface of the image pickupdevice is C, wherein the distance is calculated as a distance at whichan influence of the alpha ray based on a range of the alpha ray emittedfrom uranium contained in the cover glass is reduced.
 7. The methodaccording to claim 5, further comprising, removing the film at a portioncorresponding to a scribing line after forming the film on the coverglass.
 8. An electronic apparatus provided with a semiconductor deviceand a signal processing section, wherein the signal processing sectionis configured to process a pixel signal outputted from the semiconductordevice, the semiconductor device comprising: an image pickup device; acover glass, wherein the image pickup device and the cover glass arebonded to one another; a film provided between the image pickup deviceand the cover glass, wherein the film has a specific gravity value oftwo or more and is configured to shield an alpha ray that arises fromthe cover glass; and a transparent resin filled between the image pickupdevice and the cover glass, wherein the film is configured to cover anentire area of the transparent resin within a pixel region.
 9. Thesemiconductor device according to claim 1, wherein the film is providedseamlessly on the cover glass, and wherein the film is configured tocover an area of the cover glass such that the area of the cover glassis equivalent to an area of the film.
 10. The semiconductor deviceaccording to claim 1, wherein the transparent resin is configured tocover an area between the film and the image pickup device.
 11. Thesemiconductor device according to claim 1, wherein the cover glass andthe image pickup device are bonded such that a distance between thecover glass and an imaging surface of the image pickup device is basedon the determined specific gravity of the film and a specific gravity ofthe transparent resin.
 12. The semiconductor device according to claim1, wherein the film that has the specific gravity of two or more is anoxide film.